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1.
Sea ice
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Sea ice arises as seawater freezes. Because ice is less dense water, it floats on the oceans surface. Sea ice covers about 7% of the Earth’s surface and about 12% of the world’s oceans. Much of the sea ice is enclosed within the polar ice packs in the Earths polar regions, the Arctic ice pack of the Arctic Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean, depending on location, sea ice expanses may also incorporate icebergs. Sea ice does not simply grow and melt, during its lifespan, it is very dynamic. Due to the action of winds, currents, water temperature. Sea ice is classified according to whether or not it is able to drift, Sea ice can be classified according to whether or not it is attached to the shoreline. If attached, it is called landfast ice, or more often, alternatively, and unlike fast ice, drift ice occurs further offshore in very wide areas, and encompasses ice that is free to move with currents and winds. The physical boundary between fast ice and drift ice is the fast ice boundary, the drift ice zone may be further divided into a shear zone, a marginal ice zone and a central pack. Drift ice consists of floes, individual pieces of sea ice 20 metres or more across, the term pack ice is used either as a synonym to drift ice, or to designate drift ice zone in which the floes are densely packed. The overall sea ice cover is termed the ice canopy from the perspective of submarine navigation, another classification used by scientists to describe sea ice is based on age, that is, on its development stages. These stages are, new ice, nilas, young ice, first-year, new ice is a general term used for recently frozen sea water that does not yet make up solid ice. It may consist of ice, slush, or shuga. Other terms, such as ice and pancake ice, are used for ice crystal accumulations under the action of wind. Nilas designates a sea ice crust up to 10 centimetres in thickness and it bends without breaking around waves and swells. Nilas can be subdivided into dark nilas – up to 5 centimetres in thickness and very dark

2.
Chukchi Sea
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Chukchi Sea is a marginal sea of the Arctic Ocean. It is bounded on the west by the Long Strait, off Wrangel Island, the Bering Strait forms its southernmost limit and connects it to the Bering Sea and the Pacific Ocean. The principal port on the Chukchi Sea is Uelen in Russia, the International Date Line crosses the Chukchi Sea from northwest to southeast. It is displaced eastwards to avoid Wrangel Island as well as the Chukotka Autonomous Okrug on the Russian mainland, the sea has an approximate area of 595,000 km2 and is only navigable about four months of the year. The main geological feature of the Chukchi Sea bottom is the 700-kilometre-long Hope Basin, depths less than 50 meters occupy 56% of the total area. The Chukchi Sea has very few compared to other seas of the Arctic. Wrangel Island lies at the limit of the sea, Herald Island is located near its northern limit. The sea is named after the Chukchi people, who reside on its shores, the coastal Chukchi traditionally engaged in fishing, whaling and the hunting of walrus in this cold sea. In Alaska, the rivers flowing into the Chukchi Sea are the Kivalina, the Kobuk, the Kokolik, the Kukpowruk, the Kukpuk, the Noatak, the Utukok, the Pitmegea, and the Wulik, among others. Of rivers flowing in from its Siberian side, the Amguyema, Ioniveyem, the International Hydrographic Organization defines the limits of the Chuckchi Sea as follows, On the West. The Eastern limit of East Siberian Sea, a line from Point Barrow, Alaska to the Northernmost point of Wrangel Island. The Arctic Circle between Siberia and Alaska, common usage is that the southern extent is further south at the narrowest part of the Bering Strait which is on the 66th parallel north. The Chukchi Sea Shelf is the westernmost part of the shelf of the United States. Within this shelf, the 50-mile Chukchi Corridor acts as a passageway for one of the largest marine mammal migrations in the world, in 1728, Vitus Bering and in 1779, Captain James Cook entered the sea from the Pacific. Since further progress for that year was impossible, the ship was secured in winter quarters, even so, members of the expedition and the crew were aware only a few miles of ice-blocked sea lay between them and the open waters. The following year, two days after Vega was released, she passed the Bering Strait and steamed towards the Pacific Ocean. In 1913, Karluk, abandoned by expedition leader Vilhjalmur Stefansson, drifted in the ice along the northern expanses of the Chukchi Sea and sank, the survivors made it to Wrangel Island, where they found themselves in a hopeless situation. Then Captain Robert Bartlett walked hundreds of kilometers with Kataktovik, an Inuit man and they reached Cape Vankarem on the Chukotka coast, on April 15,1914

3.
Lead (sea ice)
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A lead is a large fracture within an expanse of sea ice, defining a linear area of open water that can be used for navigation purposes. Leads vary in width from meters to hundreds of meters, as is the case for polynyas, leads allow the direct interaction between the atmosphere and the ocean, and are important for Arctic sea ice ecology. Additionally it has been found that ice leads contribute significantly to the amount of mercury deposited onto surface. If the air is cold enough, the water within a lead quickly refreezes, such that in many cases, unlike polynyas, which tend to occur, and remain, at a given location, leads are transient features that can form anywhere in an ice-covered ocean. Lead formation is therefore tied in with synoptic-scale weather patterns, typically lasting a few days, Sea ice is often classified according to whether or not it is attached to the shoreline. If attached, it is called land fast ice, otherwise, it is called drift ice and is free to move with currents and winds. This is why leads typically belong to the ice zone. They are seen as a stress relieving mechanism, in response to divergent current flows or the effects of wind, leads are cracks or fissures that initiate inside an otherwise continuous sea ice cover, and open up progressively afterward. They are linear features, though generally not rigorously straight, as they may comprise any number of short offsets at an angle with the trend of the initial crack. This crack may cut right across both thin and thick ice, depending on the state of stress within the drift zone, leads may also close up. As the two sides converge back toward each other, this can lead to finger rafting of the new ice inside the lead. Once a crack occurs within the ice cover and begins to expand to make up a lead, because wind fetch inside a lead is typically very short, wave action is considerably reduced. Ice growth therefore takes place in a low energy regime environment, following a stage of frazil ice formation, which sometimes results from seeding by snow crystals, the resulting thin ice skim is followed by the growth of congelation ice. In windier regions, as in the Southern Ocean, frazil ice accumulation may occur along the side of leads. If the ice on that side is thin, the frazil may be driven below that ice, as ice begins to form inside a lead, it incorporates some of the salt in the seawater but rejects most of it. This brine then sinks, inducing convective processes in the column below. There are a few types of leads, A blind lead is a lead that is closed off – both ends terminate within the ice zone. A flaw lead is a lead that forms between the fast ice zone and the ice zone

As ice melts, the liquid water collects in depressions on the surface and deepens them, forming these melt ponds in the Arctic. These fresh water ponds are separated from the salty sea below and around it, until breaks in the ice merge the two.